This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Summary of TONIC Treatment of Non-Alcoholic Fatty Liver Disease in Children (TONIC) is a study sponsored by NIDDK and NICHD. The objective of this study is to determine whether 96 weeks of treatment with either metformin or vitamin E leads to a sustained reduction in serum ALT in non-diabetic children with Non-Alcoholic Fatty Liver Disease compared to treatment with placebo. It is a phase III randomized, multicenter, masked, placebo controlled clinical trial. There are 3 treatment groups- Group 1 - Metformin, 500mg PO b.i.d. and vitamin E placebo b.i.d. Group 2 - Vitamin E, 400 IU natural form PO bi.d. and metformin placebo b.i.d. Group 3 - Metformin placebo b.i.d. and Vitamin E - placebo b.i.d. Population - Children with NAFLD aged 8-17 years at first screening visit. Study duration - per patient - Up to 16 weeks (112 days) of screening prior to randomization, including at least 3 months of drug washout for those using antiNAFLD or antidiabetic medications prior to randomization - 96 week treatment - 24 week post treatment follow up Study duration - per calendar time - Recruitment phase: August 2005 - December 2006 - Follow up phase: August 2005 - February 2009 Number of clinical centers - 8